Saving a new DKIM key removes all others
When you generate a new DKIM key on the email_domain page while the server also maintains the DNS it will wipe other dkim records.
It queries for all _domainkey's: '%._domainkey.'.$dataRecord['domain'].'.') while it should just look at the old record it there is any.
The current code would also delete a dkim record for an extra external service like mailchimp.